RNZ reports on Monday, an American news agency published a release from Red Warrior Entertainment, claiming Tonga's Cabinet had formalised an agreement including a casino, more than two weeks ago.
In a statement, the government said a proposal was received in November for a development known as the Tavake Tamafua Tourism Investment Project.
The proposal included an airport hotel and shopping mall, luxury villas and a gaming resort.
The statement said Cabinet supported the project subject to legal documents, plans and due diligence.